In recent years, electronic apparatus incorporating a touch panel have come into wide use. And touch panels which allow users to make intuitive manipulations have come to be used widely as devices for receiving input manipulations on electronic apparatus including cellphones. Touch panels enable, through the same screen of a display unit (e.g., LCD (liquid crystal display) or organic EL (electroluminescence) display) provided in an electronic apparatus, reception of an input manipulation on the screen and display processing for a processing result of the electronic apparatus.
On the other hand, touch panels capable of detecting coming into proximity of an indication medium (e.g., finger) have appeared. In touch panels of this kind, signals detected in accordance with a finger movement in a space that is spaced from the surface of the touch panel and is in a prescribed height range can be used like signals produced as a result of a slide manipulation that a finger is moved across the surface of a touch panel being kept in direct contact with it. As such, touch panels of this kind are expected to become a new user interface.
Users make manipulations on touch panels in two kinds of manners: a direct manipulation with a finger of a bare hand and a manipulation with a finger of a gloved hand (e.g., the glove is made of a transparent or semitransparent resin). It is necessary to set touch threshold values for both cases, that is, the case of manipulations with a bare hand (hereinafter referred to simply as “bare hand manipulations”) and the case of manipulations with a gloved hand (hereinafter referred to simply as “gloved hand manipulations”). For example, in the case of capacitance touch panels, the touch threshold value is represented by a capacitance value. And it is judged that a touch manipulation has been made if a capacitance value that is larger than the touch threshold value is detected.
The touch switch disclosed in Patent document 1 is known as a prior art technique relating to the touch threshold value for bare hand manipulations and the touch threshold value for gloved hand manipulations. In this touch switch, a touch threshold value for bare hand manipulations and a touch threshold value for gloved hand manipulations are held in advance. And it is judged tentatively that a touch has been made if the touch threshold value for gloved hand manipulations is exceeded for a prescribed time or longer even if the touch threshold value for bare hand manipulations is not exceeded. Furthermore, in the touch switch, when it is judged tentatively that a touch has been made, the tentative touch is judged a true touch unless a bare hand touch is detected at another position on the touch panel.